Everyone wants to get something for nothing - whether it's a lucky upgrade that means you can turn left when you get on a plane instead or heading off into the economy seats, or even getting a few extra features thrown in for free when you buy a new car.

As some of the sharpest businesses around, no-one understands this quite as well as casinos and that's why they all have a system that they call comps. It's short for "complimentary offers" and these are special treats specially designed to reward you for your loyalty to the casino in question. They're basically bonuses.

HIV-positive 71-year-old Sylverio Hachiploa (R) talks with caregivers Glandwel Muleya (L) and Sister Abigail Mwaka Mazuba (C) in his thatched hut during a visit by a home-based care team in the village of Nedwmba, south of the Chikuni Mission in the south of Zambia February 23, 2015. The caregivers in the Jesuit-run home-based care project at the Chikuni Mission run a capacity-building and empowerment project at the household level, offering training and assistance in crop-growing and animal rearing, as well as offering companionship, pastoral care and monitoring of the antiretroviral treatment compliance of HIV-AIDS patients. (Photo by Darrin Zammit Lupi/Reuters)

Londoners walking through Potters Field Park were surprised to see a “money tree” blooming with £9820 in £10 notes, the average amount a working British family has in savings, on July 24, 2014 in London, England. The tree was planted by Sunlife to encourage the nation to start saving at least £10 a month for a brighter future. (Photo by Tristan Fewings/Getty Images for SunLife)

A motorcyclist dodges in the annual water-splashing festival to mark the New Year of the Dai minority in Menglian, Yunnan province April 13, 2015. (Photo by Wong Campion/Reuters)

Alaa, an ambulance driver, feeds cats in Masaken Hanano in Aleppo, September 24, 2014. Alaa buys about $4 of meat everyday to feed about 150 abandoned cats in Masaken Hanano, a neigbourhood in Aleppo that has been abandoned because of shelling from forces loyal to Syria's president Bashar Al-Assad on it. Alaa said that he has been feeding and taking care of the cats for over 2 months. (Photo by Hosam Katan/Reuters)

Actress Michelle Rodriguez attends the Shane Black 9th annual Hallowen party held on October 31, 2003 in Hancock Park, Los Angeles. (Photo by Frazer Harrison/Getty Images)

In this July 8, 2019, photo, a monkey pulls on the clothes of Saraswati Dangol as she arrives to feed monkeys in the forest near Pashupatinath temple in Kathmandu, Nepal. For the past four years, Dangol has been bringing the bread every day to feed the monkeys. As soon as they see her with her white sack, they gather around her, some patiently waiting for their turn while others less patiently snatching the bread from her hands. Many of Dangol's regulars are elderly, or are mother or baby monkeys who are unable to fight for their share of food in the wild. (Photo by Niranjan Shrestha/AP Photo)

These adorable pawtraits seem to show the personalities of a variety of canines, capturing their incredible diverseness in their expressions and fine details. Khokhlov and Ershova, who are from Moscow, have taken portraits of about 50 breeds of pooches – earning much critical acclaim. (Photo by Alexander Khokhlov/Veronica Ershova/Caters News Agency)